<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
<form action="5demo.php">
    <select multiple="multiple" name="n1[]" size="10">
        <option selected>张三</option>
        <option selected>李四</option>
        <option selected>王五</option>
        <option selected>赵六</option>
        <option selected>frank</option>
        <option selected>tom</option>
    </select>
    <select multiple="multiple" name="n2[]" size="10">
        <option>张三</option>
        <option>李四</option>
        <option>王五</option>
        <option>赵六</option>
        <option>frank</option>
        <option>tom</option>
        <option>jack</option>
        <option>andy</option>
        <option>lucy</option>
    </select>
    <input type="submit">
</form>
</body>
</html>